Two-stroke internal-combustion engine



' Aug. 19, 1930.

- w. TQBLER TWO-STROKE INTERNAL COMBUSTION ENGINE Filed Oct. 20, 192

Patented Aug. 19, 1930 UNITED STATES PATENT OFFICE WERNER, 'lOBllLER OFIVINT ER TI-IUR, SWITZERLAND, ASSIGNOR TO THE FIRM F SULZER FRERESSOCIETE ANON'YIYIE, OF WINTERTHUR, SWITZERLAND TWO-STROKEINTERNAL-COMBUSTION ENGINE Application filed October 20, 1928, SerialNo. 313,696, and in Switzerland 0ctober 24, 1927.

This invention relates to multi-cylinder two-stroke internal combustionengines and has for its object to provide an engine in which the noiseusually caused by the scavenging air pumps will be reduced to a minimum.

According to this invention the casing which connects or unites in asingle block the various engine and scavenging pump cylinie ders isprovided. with a separate air inlet opening for each scavengingcylinder, this casing being so constructed that it serves to connect theair supply chambers of the individual scavenging cylinders.

One construction according to the invention is diagrammaticallyillustrated by way of example in the accompanying drawing, wherein Fig.1is a diagrammatic plan view partial- 2o ly in section on line I-I ofFig. 2 of a coni istruction in accordance with the inventione Fig. 2 isa diagrammatic cross sectional View on the line II-II of Fig. 1.

The example shown has three engine cylin- E5 ders a arranged above thescavenging pump cylinder 6, and the products of combustion aredischarged through the exhaust pipe 0. The pumps, together with theengine cylinders, are mounted in a casing e by which they are connectedtogether to form a rigid block, and each pump has an inlet valve d. Thechambers or free spaces f within the casing from which the pumps drawthe scavenging air, communicate with one another as shown at h to formin efiect a single suction chamber and the chamber so formed has aseparate air inlet opening g for each scavenging pump.

It has been found that this ensures an almost noiseless admission of airthrough the openings 9 and therefore a considerable reduction in thenoise hitherto made by the scavenging pumps. It will moreover beunderstood that, if desired, the pump delivery chambers may also beconnected together .(like the suction chamber f) to form a single orcommon chamber within the cas 5 combustion engine having engine andscavhaving therein an. air inlet opening for each of said pump cylindersand a plurality of inter-connected air supply chambers forming a commonair supply chamber connecting with all of said pump cylinders.

In testimony whereof I have aifixed my signature.

WERNER TOBLER.

